This invention relates generally to duplicating machines and, more particularly, to ink fountain assemblies for use in duplicating machines.
Printing machines, such as rotary offset lithographic duplicating machines, normally include a printing couple which comprises a number of cylinders and/or rollers such as impression cylinders, master cylinders, blanket cylinders, ductor rollers, regulator rollers, and the like. An ink fountain is disposed at the rear end of the machine for feeding ink to the various rollers of the printing couple which transfers images to copy sheets.
Conventional ink fountain assemblies normally take the form of a fountain trough defined by an elongated blade extending along one side and an ink fountain roller extending along the opposite side of the trough. The ink fountain roller transfers the ink to the other rollers of the printing couple. The blade is adjustable by a plurality of thumb screws to vary the gap between an edge of the blade and the ink fountain roller in order to maintain consistency in the amount of ink applied to the roller uniformly along the length of the roller. The adjustable blade and ink fountain roller are mounted on brace assemblies at the rear end of the duplicating machine and permit ready removal and/or replacement of the fountain.
One of the problems with ink fountain assemblies of the character described is leakage of the ink between the ends of the adjustable blade and the ink fountain and between the ends of the roller and the ink fountain. Although ink used in printing machines, such as rotary offset lithographic duplicating machines, is a rather viscous liquid, leakage continues to be a dominant problem.
Heretofore, the problem of leakage has been combated by attempts to maintain very close tolerances and precise fit between the adjustable blade, the ink fountain roller and the ink fountain. However, even close tolerances of these various parts of the ink fountain assembly have not completely solved the leakage problem.
There is a need for an improved ink fountain assembly for use in duplicating machines to substantially eliminate the problem of leakage from the fountain trough. This invention is directed to satisfying that need and overcoming the problems outlined above.